SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46b4d0bd27eafdc73778fcd05230f5cfa27992bca50489050e9f990f1af5e4cb' 
  AND token = 'F/8jPdHCtiiZwnGknkMiq/p/vhBWCAaz/sTOh4R1nGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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