SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f40cecbbc1027dbf49a00873260fad18cd2bffd994172cb648034844ef0665a' 
  AND token = 'PsLOdwiAqAo7kVKSPjYfWyQoWC4AA2j0JkodzlZrf9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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