SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a69abf4fd9675676b478cfce57c298e2007abd6a3b35992a07cd15281a7da0b3' 
  AND token = 'lwzAsLGEhwzL5JxHXY+vYXKK2Cle9tTSe5ZpKtyybRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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