SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2ca96555f1c031b56d0fac262a956283cf8bec0c9a48943024cb24f2445b470' 
  AND token = '83fEq3s3F0rPWg5CfKMldVeA3sf0H+6GfFkSRfEIK/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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