SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '564c407f36a46d6e82706048e54fbedc51b9ee0c0627ec472437cadca9039aee' 
  AND token = 'q/ny9df6jNCwnN60Otcy+OlQ1qdUbylnaltFxr5UYrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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