SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9853a5b7412064e05eea018159d11132637ad4c2bc6cfbbadc4d1812471034ab' 
  AND token = 'U5LexC3cg0/uDABeeJNtHIDfkknNRxcVGs7Art7E3CA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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