SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efc6b6c2b8c5d79c4f093739bfcf584f2fa7efb1524d2a06cba42763379a7745' 
  AND token = 'sud6XwzoFJxaJaneTNwswzQgSFXFfXrG2ELHAhBheKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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