SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be9ddbfc314ced80579163396895aca6ed2b63fc5b18746dcac62fcc9c4f03f9' 
  AND token = 'fyE/DT4ggYdRAvJucZFnqbvbXjzYjsmq/o/GnXpFYbM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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