SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e042134d56f3a1f139b9927eda4dd8d0047035c67381beeb358f44688c379f4' 
  AND token = 'I9p2oOsIlPBScTu2clwZP40mj9B3uKKVPLn5lM5k2Ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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