SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe73637b7d00fdd5777d1f857f74b49a370405c231235bba0b8bb2590897c32e' 
  AND token = '7wHVPq3apNHmOERhVZf3Xl9h4cvEOtU9WHeGYYisRPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}