SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34c2f39ca02200e1c93ff4b0fd30babeef43a1f68f9d3f029f591275cd1f1463' 
  AND token = 'grrjbKz+AGq2gUwERiygbDHBbNIKumblPWulTCBZ8LY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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