SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37d36116a24f5dbddd3ea87594a7a6c20252fb306e8f749a81fbb01c980abfca' 
  AND token = 'ST7K3aqz1ViPGcWUTdCpit5lkt6qWhXUmzlUrxAw7Is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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