SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c9fc63258a052d978ba4425cf4d2b5e06737bcf33d350832c5ef599ef0f01a8' 
  AND token = 'V7jXu6Iqj0V0/9lbkxdwCo2Gh/ppXJzcldLj+C9Z+xE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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