SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70a1e215f009f55644d8dfa87320775321d73edd005acadcfc1b276de0a9a0a1' 
  AND token = 'IK2VvQ4JrdGNiKlG9IlU9mcOgVK3cu9gkhXosSy1fI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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