SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dba7c7a6f5feebd395cf47827227acb036f77bb961d1a31a46848014f566c3b4' 
  AND token = 'PkcJ5Psrf2q4t6FLFh21w4k6WlNIAxJTBBfrZPJU2mM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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