SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '52e5071d28e8666e0a21ca9184be0a99d2ad430af534be0055a789d77f60c379' 
  AND token = 'K6gpTeSDdGhs3K+whnZ2AVazBlKy1PJ2AWqahsnVEII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}