SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f6c02513bd4529e02af3c1cb14a19d82a658700c9745fe47ed8289fa2757b73' 
  AND token = 'WLbvgkmuD3DFZ+7WIfE1aBKgmL2vYyFKQEnx0U8Hgog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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