SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af0ec0c4deaefe55bc43659248afd25cfe93b8f8afa1b168479b1681a72e08ed' 
  AND token = 'Q3VWY5NA0Ybu6uSFtxztQbD9lG9+cojNDxkFZHBtmRs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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