SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1e02558a290a3d2613d5c91a0085010018405afa2518c239c389d2547ae2bd9' 
  AND token = 'F5CFGlA7Bw4KrZSAOgaMlUpFiUuCVOLCJhNtHONcUoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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