SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97043a10f036132f2c1959b52a34b6624e1c9d43c5cb8bfe4e5d5c3e3690b8e2' 
  AND token = '8mHYPHBdlKyJS5ypDjnPCmVUSoCwJ3d3xMHalDR26LU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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