SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '93d0856c6404199408e55d6d6697f6db916af88f7940412f140a3ded47edb24e' 
  AND token = 'M6GidDBnaOLQe4zMRiGcT/wyPd4uONBUi3RUTPX8PlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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