SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '951ec76a80b638741f9b103ffcfff97c3fe861ac26e51a0d7b8ca85896874fd4' 
  AND token = 'B84KNRcG+X3dUUZWkbiG74LXePaCTglAjEcQKOA7nZI=' 
  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"
    }
  }
}