SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b29b62f756be91c330ede06bbb7dbb943d78ef97d8aac1680eb8c068de1d289' 
  AND token = 'P5OPR4mvQnilI74uLxG+pZjpa4fOCnK2VP/mnswJ510=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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