SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3507915f681e0f9a604fd4145df42364fcd148e252ddd0eea97e0050bcc2598d' 
  AND token = 'S3n28pHfQzvz9ku5iow86c8YH6IzJnKjJGBJI6in3M0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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