SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d24e60d1af71dc9c4bc5137f5240f38436ccc65c983651bb37734d6a34cf07' 
  AND token = '2bI9gD/vhIXz07SD+yBoavEwwYx8d4DilWhvQvWFq0w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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