SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'debb0623817994516367b24177a67f7528c3f5ace9f2891a73722d1a2efedafe' 
  AND token = '5TduwuFB3dI6JineGq/xFcHfngS8a5z9STTmWV//4A8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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