SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19896db3223f5d145c8c87595b59cdfb1f0c265ed30e43e7976c46cb81517581' 
  AND token = 'a8igP48i+tYsAX6fnlmoOGsWLtVIQh8z4AhCc+FZ0Qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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