SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebe587ab2d38576f5a0c3c6858e755dfab688d9740ba92c2326b7206377be470' 
  AND token = '+4PrXkiALMwQbiPgQANVTHK3gv5aGXFnfWzLGJ7OSUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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