SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eda5d660532ebd8cc946e515968e045af4322521cae8779f413c81abad9c99c6' 
  AND token = 'TNyv3ShN150EOpwW5El8eb3C1sw4HlJCz7TwI4kNh4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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