SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e915442cc34e54acc0fc440254849e3ffb49d186b7fc8148130d470406dbf875' 
  AND token = 'qszqH18yabR+VrjlzOXvBoJBaKIcbXrOId3zvQ2Duyw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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