SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb6a467a3bfd823b326d49bd38af2ad381ff109fdfa6a98a249ead32a29d9e36' 
  AND token = 'hjU18o6KfEJ/cY8WwiR1akhWyWXdMwOjFCMinKdwll4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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