SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '285a94630ceec001402ea2e9d5fa79f177975d0a9c30adb4e1e1bbcfa10829fa' 
  AND token = 'ivlyMx9+JKnCAT1iwYVtAh7YPL5EeVlWVUBC3Ec+1DY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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