SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97b7470fceabef555d5fb2fadbbf2630de96284a0e5459a5b38a15d9b4ecaeeb' 
  AND token = 'VP8Q2sjwS7pLjfrz/62nd+zu9rM2PzJXYv9ZdYsQdkY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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