SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58b953c7a5c5162d5a46a6a6266fb9a428b85e896678f464995a3d76742bbcae' 
  AND token = 'KaZEyvrMritBmnX/sK+gu2Qjrgyy8FTWjBD5XSIPEqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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