SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '957a7b4e061e67c838dde42ba953c476558243a2bed5758093025129203b1284' 
  AND token = 'oY7KPWqN/Fycry1+n2JhCiRFGhMNke8Vz377R876MgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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