SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f98fc2be40d9931d9127d47b81073a3f57ce68252c87de55a880c1dfa3ae454c' 
  AND token = 'JTPLBakq8ogbAN4b1BY2Y0kupv1UXmUwThaqJgcJ74g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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