SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b424d70a40e30ab8de472f8bd0f52832e521bc4a86afea16cecf197166451a4d' 
  AND token = 'ON1qIXVZ3/oOBkjPtDPQ01frs9xn5Gv9MKXlASaOiLc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}