SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd4b4ba6919e980d07df99c46f1907ad715f0f732b058b990c1fbea201b8effb5' 
  AND token = 'MP/Bk59FvB+v/ZawEHxTJtzGt7/jU83wqc6gNbIpYwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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