SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc507745c71b34835478a2bc39e101f7c6027cf76cd6c7f29f49dd1b1f2cf5bc' 
  AND token = 'adxsLhk+NEJutmkbOwU6JYQ2uJ4vFXFLfoVdGQzDVcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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