SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c1ebb8af315fa9f173fc97000d10dbc787a4ab0e1332903398895eff83e188d3' 
  AND token = 'UYPcJzqp86jTFnQ5KxowMYC4YZ5VlmagRsG2JJmp5UA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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