SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '1db77d6e18d1cb943ad856c1e01e520fd0806638987e4b6516c44de628e3be38' 
  AND token = 'sYXIWtUxii7qJDU0xlsNvKTbha+5W77k2R3h/l2kcLo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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