SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c4779047beba86fb07fb89cd6b9a276cf0398cf1fcc4d03cad53d640b112226' 
  AND token = 'kRn6/E4YhFllFPCQZANFsDtk8eih2oH1A3Nrv8RfaVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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