SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd674d06f83d50e759080173b8e38df56a9188c6a2e582e79ee72065f827394f1' 
  AND token = 'bxrGjVgEHTJ7VPHgZ5CHDuZI2xR/rUrJflqDCldknhg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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