SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b1bcd5996b4294ca8f1667e30abdd60fea8342a29f168016be3952281658272' 
  AND token = 'kV8Be+8RK/F4QnvSyisyNukxpuZLfMFKRnaXkN7Pzxg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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