SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef5409c717d0c11950144b682d1b4643ce34ee1aa634cacd101666b9cd084690' 
  AND token = 'xMxfEAU4AUPlOJP961QkGvi8vNMAX5uxr4Sqcnz+xsg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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