SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a74db43f3bb2db593a986c5173556683560e545fad3ea41776967626f0ab007' 
  AND token = 'SDBPGDwbQAbtzkDjrMRa1qdajMOsrMLvIcEqyMO28W8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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