SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f12901dea5b58a7706198697215c64b32126a06dce4e414bf98b557e8e376d9f' 
  AND token = '8IBPBkOhE+qG0uS/Y/D6YIce5qXbbGl2mveWS5D2s0A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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