SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf6ab852b3032426c878e1e536cf26ef874ce54a91e905ca4feed289e75ea74a' 
  AND token = '4XZsioSXYpGa1YchpQ6gLH2dmRDFjFaSO94MEt955dg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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