SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c56d3da220f95c83626553bdb280406e51420378f8f45f48e625f03bdf2c1db' 
  AND token = '5oHT0cii1R2xhO5OgIweAChhyDC/prBKRF+SX3uLLoI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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