SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31875da1d4480507ce5bb9c6ffd2b6f09f582dad6ecdc9894eff9a7380c361b9' 
  AND token = 'BNGYtbbVXcVnoaz+Itc4wxQSO1QEkzds4dxiGUDllGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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