SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1c4fb99486aa82a60452a94413d6effb8b5a1ed7ccd67448f76b503dd157c18' 
  AND token = 'jwBhlMUTGq5vbY56/MhBw8KFLoV3WXHYjGXJnDrAjF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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