SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66a513a4cc8599a30ad84a2823cf9a5b36f4fbe7166d8b0732c454e177040f40' 
  AND token = 'rXlILfgS8HszD9lDkwJhGEMH+h1668aFq54xC8vOKUE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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