SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a10cde681a3026f733dfc53bb03b75297ed7c785af74d863a21e908d20adceb9' 
  AND token = '9fh8rcU8Ei0wmyUQor5v0uJtOE8n5ApOQFKEYcmJ3J4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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