SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a077292f0c1591d66f793753c7cd702b307361ddb718a9b84ebd5351f14effb' 
  AND token = 'VagLO9vkarZWxfmAJHqck87SghyI64c5YqIgtCeiB1Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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