SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6ae2e3f44369b29ccfd28f57dadf3d651f8355e1b026f6ee19d781f9b0108b7' 
  AND token = 'HEzZJfrwiYoFMPp+EVqRierKZu7cLZ4LAakeRcV2mfA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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