SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ce55b52500c609136e4089830aa33b60a5c9bf27ad404013936f6d3d0e60f75' 
  AND token = 'q2HCNy293GLvgt3cFCeH8MmGLLu2Te2bR+M+adce0Yw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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