SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8d10c643678f967804f1f937c6bc3c3b6a5dfb065b4bf6b9cc7f3ed205f7f203' 
  AND token = 'zxEQMegOWnqI6M4IrWRbGrDvLa2oQfxTWfsnSYFBIcc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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