SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe015f106c56f743ec6351155d8e7eaca18272471c30e9d0a07decd77dc8be54' 
  AND token = 'eXr+vXSDZhHHSFo6PNmtBGHPpVHRbTQcgpESOxdpzB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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