SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73818a07f186741bc8f873fc251a2eff3fae1e7c746f79eed34725d9970e2028' 
  AND token = 'bjb86OnIkuBFAMA5c7vRUG/ONitqJ4BYLjlXeLVXwnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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