SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fb803f5da19fe74790bfa18925ca688fc51bc0b528824efe2b466c8fff21390' 
  AND token = 'jp+e/8fSgoVfNHQZcn3XKF9XXeyZCVPmgF2HJHZRzh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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