SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d4a62df6980ff4b687798333a5f1d1ea3c3743efc2676a04511cf88904da140' 
  AND token = 'E4hEJ1ZjxX6KGsjVglu7JB1NILiKydeBbCx1HPIQZ1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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