SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cdbf2d3879442cec0bf9f26254f03f0813b5d5c60f2e4a9a46d29d5492baff6' 
  AND token = 'GClU0RQCZmguezkNGcdeBTVcLxM+pQbhGdT1Hp8Y/SQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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