SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50502379a9c18b402e0310e656c861483c819f1b1a0441dd3ee0222a49ca2baa' 
  AND token = 'VefijneFiU0XzrTTd7jG8GwFCYFVzikrSZyfX7BAnoo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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