SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2825ddaefed8261bcc5443d662f13c8bbe711ef91c0b82d3e49896805d30119' 
  AND token = 'tm5zym64irzvmJWGlm+b3eKOMeAor3mVdEzWKu7AzBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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