SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fb52faf95b5bf235aca90c436eade2eec7c03dfcafbfe58c976158ee7ea90f3' 
  AND token = 'RqGFbsf6VPbjA7pbBAKMIScBcbuBukQS2xCbPH4Sofg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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