SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f91f782293d4b82a9c8597e02a00d866aad503675d0cbb1b5a6d0206f3c3698' 
  AND token = '7ilToM6LBzx19j3tGleCRyWr1ELzRd20f7YD9Tmpm9c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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