SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7156a2dec0c31118e11ed644ad1393cd2f212a7f0fc62a2c66929030880e271' 
  AND token = 'Axzs3jOXMklD/OBQeakdfa/aublvOzmQ7FbVmGhvRqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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