SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a49e6205eca03e915b7ffbce353fc762b12c53e5e943ab6cb0cc9e1df26be454' 
  AND token = '+XxjsBLMfhoVt1dU6xFDOG3QE3rovZKIC0JqRgQYXKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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