SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '562d63df738e1b06ce547aec645cb403ebec98cd64f8fd4a27b06f82a8ac5921' 
  AND token = 'SWsSSKQBtUsV7LKia/VGyIJwWAVWB4diR0rJktanKRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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