SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f682da37313ad69b93fc465a8f95d541e8b0903ccd76be2d9051eb06edca35b' 
  AND token = 'QSTUJ9B+PPVQEGjTCK3sPud50b+nXHcWDWkZS7ihuL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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