SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '41e26c655e1e2225e78bf4663108adecc443abad3c11af3338da15598123426a' 
  AND token = '82mspHWEvO80mGyynmnPaPRFWmmmQyAtHeKz8499As4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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