SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f1bd8838fb63cd2343acf8251393946ada32d214d506884dff8bdc967a5aee0' 
  AND token = 'i2ro0ILsdEuQ7GGj/Y96tKCjfav6fUnWqZ+H/I5Vwek=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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