SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16bd6de91952207234f1ae7bb24c4d1722f22afb69814672f513500a4989cfe7' 
  AND token = 'SMlTuhxIOYawZfV1bFYDIAhbvTtHR0vWoBeO8T51hsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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