SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '581eff24f8489259e929649592baf016700c44184daeeb184ce3fecd160f1f13' 
  AND token = 'MQAQNQ1USK1cuX67fO2dJIp5MU3lLs98dI+IA0ajHVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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